During substrate processing, such as etching process, an inner volume of a process chamber may be exposed to one or more process gases. Often, such process gases are provided at desired flow rates controlled by one or more flow controllers that provide the process gases to the inner volume. In some process chamber configurations, for example where shared gas panels supply the process gases to multiple process chambers, the inventors have discovered that no methods exist for confirming that the process gases from the shared gas panel are being split correctly to each chamber by the flow controllers. In addition, the inventors have observed that there typically are not any on-tool apparatus available on a multi-chamber substrate processing system, such as a cluster tool, for monitoring the flow controllers of each chamber, for example, to detect drift or to compare drift between flow controllers on different chambers of the system.
Accordingly, the inventors have provided methods and apparatus for calibrating a plurality of flow controllers in substrate processing systems.